Alkyl peroxides

ABSTRACT

DISCRIBED HEREIN ARE HYDROLYZABLE FUNCTIONA SILYL ALKYL ALKYL PEROXIDES HAVING THE FOLLOWING GENERAL FORMULA   X3-N(RN)SIR&#39;&#39;OOR&#34;   WHEREIN X IS A HYDROLYZABLE GROUP, R IS HYDROGEN OR A MONOVALENT ORGANIC RADICAL WHICH IS BONDED TO THE SILICON ATOM THROUGH A CARBON TO SILICON BOND, R&#39;&#39; IS AN ALKENYLENE, CYCLOALKENYLENE, ALKARYLALKYLENE, OR ARALKYLENE, R&#34; IS AN ALKYL OR ARALKYL, AND N IS 0 TO 2 INCLUSIVE. THESE HYDROLYZABLE SILYL ALKYL ALKYL PEROXIDES ARE USEFUL AS INITIATORS FOR THE POLYMERIZATION OF MONOMERS HAVING OLEFINIC UNSATURATION AND ARE ALSO USEFUL IN FORMING SILICONES.

United States Patent 3,772,349 ALKYL PEROXIDES John Richard Joy, Stevenson, Md., assignor to Union Carbide Corporation, New York, N.Y. No Drawing. Filed Oct. 21, 1970, Ser. No. 82,854 Int. Cl. C07f 7/12, 7/18 US. Cl. 260-4482 B 4 Claims ABSTRACT OF THE DISCLOSURE Described herein are hydrolyzable functional silyl alkyl alkyl peroxides having the following general formula wherein X is a hydrolyzable group, -R is hydrogen or a monovalent organic radical which is bonded to the silicon atom through a carbon to silicon bond, R is an alkenylene, cycloalkenylene, alkarylalkylene, or aralkylene, R" is an alkyl or aralkyl, and n is 0 to 2 inclusive. These hydrolyzable silyl alkyl alkyl peroxides are useful as initiators for the polymerization of monomers having olefinic unsaturation and are also useful in forming silicones.

This invention relates to silyl alkyl alkyl peroxides having at least one hydrolyzable functional group, such as alkoxy, aryloxy, halide, amino, acyloxy and the like, bonded directly to the silicon atom thereof. This invention also relates to silicones, having siloxane units which were formed through hydrolysis and condensation of said hydrolyzable functional groups of the silyl alkyl alkyl peroxides.

It is known that it is difiicult to initiate the polymerization of monomers having olefinic unsaturation while achieving a polymer having terminal end groups capable of further reaction. The silyl alkyl alkyl peroxides pursuant to this invention will readily thermally free radicalize through the alkyl alkyl peroxy structure to permit such polymerization initiation. Upon such polymerization, the presence of hydrolyzable functionality on the silicon atom results in a chain terminated polymer having desired hydrolyzable functional end groups which are capable of forming bonds to polar substrates.

Certain acyl peroxides are known in the art and have been used as vulcanizing agents for rubber and also as polymerization initiators. U.S. Pat. No. 2,963,501 discloses nonhydrolyzable organosilyl peroxides formed by the reaction of the corresponding nonhydrolyzable organosilicon alcohols with peroxides in the presence of sulfuric acid. This strong acid reaction would cause bydrolysis of a hydrolyzable organosilicon alcohol and thus is incapable of providing hydrolyzable functional groups on the silicon atom.

US. Pat. No. 2,970,982 discloses different classes of diorganopolysiloxanes having a tertiary alkyl peroxy terminal group which peroxy group is directly bonded to the terminal silicon atom of the polysiloxane chain. These materials are not silyl alkyl alkyl peroxides as described herein.

This invention relates to silyl alkyl alkyl peroxides such as alkyl alkyl peroxy silanes (alkylperoxyalkylsilanes) having the following general formula:

wherein X is any hydrolyzable functional radical such as alkoxy, aryloxy, halide, amino, acyloxy and the like; each R is one of hydrogen and a monovalent hydrocarbon radical such as alkyl, alkenyl, cycloalkyl, aralkyl, aryl and the like; R is an alkenylene, cycloalkenylene, alkarylalkylene or aralkylene radical; R" is an alkyl or aralkyl group; and n is an integer from 0 to 2 inclusive.

This invention also relates to the hydrolyzates and condensates of the afore-described hydrolyzable functional silyl alkyl alkyl peroxides, whereby siloxanes are formed. It is understood in the art, that when n equals 2, the resultant hydrolyzate and condensate is a disiloxane. When n equals 1, the hydrolyzate and condensate is an essentially linear siloxane and when the silane is triflunctional, that is, when n is zero, the resultant hydrolyzate and condensate contains siloxane cross-linkage.

The alkyl alkyl peroxy siloxanes pursuant to this invention can have any degree of polymerization and may range from fluids to non-flowing gums to resins wherein they possess the formula:

wherein a is O, 1 or 2; b is 0, 1, 2 or 3; x is a number greater than 1; y is 0 or a number of at least 1; and each R, R and R" is one of the radicals defined above therefor. Copolymerization with a broad range of siloxane is possible.

Illustrative of X are any hydrolyzable functional radicals such as halide (such as bromide, chloride and fluoride), alkoxy (such as methoxy, ethoxy, propoxy, dodecyloxy, ispropoxy and the like): aryloxy (such as phenoxy, naphthyloxy, triphenylmethyloxy, and the like); acyloxy (such as acetoxy, propionoxy, and the like); amino; alkylamino and arylamino (such as methyl amino, diethyl amino, phenyl amino, and the like); hydroxy alkoxy (such as beta-hydroxyethoxy, gamma-hydroxypropoxy, and the like); chloroalkoxy (such as betachloroethoxy, beta-chloro-propoxy, and the like); hydroxy; alkoxy, alkoxy (such as beta-hydroxyethoxyomega-hydroxy-(polyethyleneoxy); ethoxy; omega-hydroxy-(poly-1,2-propyleneoxy), and the like).

Illustrative of R is any monovalent hydrocarbon radical, such as alkyl of from 1 to 18 carbon atoms (such as methyl, ethyl, n-pentyl, n-dodecyl, n-octadecyl, 2- ethyl-n-hexyl); cycloalkyl (such as cyclobutyl, cyclohexyl, and the like); aryl (such as phenyl, naphthyl, biphenyl, and the like); alkenyl (such as vinyl, allyl, methallyl, 3- butenyl, and the like); alkaryl (such as tolyl, xylyl, 2,4- diethyl-phenyl, 4-dodecylphenyl, and the like); aralkyl (such as phenylethyl); and the like.

Illustrative of R is a divalent hydrocarbon radical of from 1 to 18 carbon atoms such as alkenylcne (such as vinylene, propenylene, l-butenylene, Z-butenylene, 2- methyl-propenylene, and the like); cycloalkenylene (such as cyclopropenylene, 2,3-cyclobuteneylene and the like); aralkylene (such as phenylethylene, phenyl-propylene, 1- (4-methylphenyl) butylene, 3-ethylphenylethylene, naphthylethylene, and the like); alkarylalkylene (such as 1-4- methylenephenylene, 4-(ethylene) cumylene, 1-methyl-3- S-methylenephenylene, p-cymenylene and the like).

Illustrative R" is an alkyl group from 1 to 18 carbon atoms; ethyl isopropyl, octadecyl, 2,2,4-trimethylpentyl; cycloalkyl groups included are cyclopropyl, cyclobutyl, cyclooctyl, 1-methyl-2-ethylcyclohexyl, and the like; or an aralkyl group of from 1 to 18 carbon atoms such as ethylbenzyl, cumyl, triphenylmethyl, n-butylbcnzyl, betaphenylethyl, and the like.

The silyl alkyl alkyl peroxides pursuant to this invention can be prepared by the catalytic reaction of an alkyl or aralkyl hydroperoxide with an organosilane containing at least one hydrolyzable functional group and also having a hydrogen capable of abstraction as follows: X (R )SiRH+2HOOR"- X (R )SiR'OOR"+HOR"+H O wherein the H of the organo silicon compound is bonded' to an allylic carbon atom of R when R is alkenylene or cycloalkenylene and H is bonded to a benzylic carbon atom when R is alkarylalkylene or aralkylene; X, R, R, R and n are hereinbefore defined.

The catalyst in the above reaction is a metal salt, preferably a copper salt, such as cuprous chloride or copper sulfate and is employed in combination with an organoamide such as benzamide, acetamide, N-methyl acetamide and the like. Benzamide is the preferred complexing agent when used in conjunction with cuprous chloride.

The above reaction is carried out in the presence of a solvent such as aliphatic hydrocarbons, such as hexane or heptane, cycloaliphatic hydrocarbons such as cyclopentane or cyclohexane, aromatic hydrocarbons, such as benzene or toluene, and the like.

The operating temperature in the above reaction is not critical, but is advantageously between 25 to 100 C. and the reaction is carried out for periods up to about 25 hours or more, if necessary.

Illustrative of the silanes suitable in the above reaction are:

In the above reaction, HO is an alkyl or aralkyl hydroperoxide.

Illustrative of such hydroperoxides are the following: methyl hydroperoxide; ethyl hydroperoxide; propyl hydroperoxide; isopropyl hydroperoxide; n-butyl hydroperoxide; sec-butyl hydroperoxide, t-butyl hydroperoxide; tamyl hydroperoxide; 1,1-diethylpropyl hydroperoxide, 1, 1,2-trimethylpropyl hydroperoxide; l-methylhexyl hydroperoxide; 1,1,2,2-tetramethylpropyl hydroperoxide; cyclohexyl hydroperoxide; 4-methylcyclohexyl hydroperoxide.

In the above reaction, HOR, is an alkyl or aralkyl alcohol which is removed from the product reaction by water dissolution at elevated temperatures, approaching the solution boiling point, as shown in Examples 1 and 2.

Silyl alkyl alkyl peroxides formed in the above reaction are for example:

triethoxy-silyl propenyl cumyl peroxide,

vinyl(triethoxysilyl)propyl peroxide,

vinyl(trichlorosilyl)cumyl peroxide,

2-butenyl(triethoxysilyl)isopropyl peroxide,

cyclopropenyl(dichlorosilyl) 4-methylcyclohexyl peroxide,

phenyl(triethoxysilyl)cumyl peroxide,

4- [2- trimethoxysilyl) ethyl] cumyl cumyl peroxide,

5-[2-trimethoxysilyl)ethyl]-3-cyclohexenyl cumyl peroxide,

4-[2-(trimethoxysilyl)ethyl]-3-cyclohexenyl cumyl peroxide, and the like.

The silyl alkyl alkyl peroxides of this invention can peroxy silanes of this invention, as stated previously, can be copolymerized with a broad range of siloxanes and cyclic siloxanes. This copolymerization is carried out in thedpresence of an acid catalyst (for example, sulfuric acr The silyl alkyl alkyl peroxides of this inveniton can be used for any of the purposes for which peroxides are generally employed such as initiators for the polymerization of olefins and as vulcanizing agents for rubbers.

For example the hydrolyzable functional silyl alkyl alkyl peroxides can be used as initiators for the polymerization of monomers having olefinic unsaturation. Illustrative of said operable monomers include the acrylic esters (such as methyl methacrylate); the alkenes, preferably those having omega unsaturation (such as propene and l-decene); the aryl alkenes (such as styrene, alphamethylstyrene and the like); the vinyl esters (such as vinyl acetate and the like); the vinyl benzyls; and vinyl biphenylene and the like. More specifically when a silyl alkyl alkyl peroxide is used as an initiator for the polymerization of styrene, the resulting polymer contains hydrolyzable functional end groups. When the said resulting polymer is heat-cured to a polar substrate, for example glass, a bond is formed which is highly resistant to water immersion.

The following examples are illustrative only and should not be construed in any way so as to limit the invention.

In the following examples, iodometric analyses to measure the active oxygen content of the product silyl alkyl alkyl peroxides, to determine purity, were performed according to the method of C. J. Pederson, as presented in 23 J. Org. Chem, 252 (1958) and said analytical procedure is incorporated herein by reference.

EXAMPLE 1 A reaction charge was prepared by mixing 7.6 grams of cumene hydroperoxide (83% purity), 26.5 grams of 4-[2-(trimethoxy-silyl)ethyl]cumene (prepared by reacting 4-isopropylstyrene and trimethoxysilane with chloroplatinic acid catalyst), 1.0 gram of benzamide, 0.20 part of copper (I) chloride and 44 grams of benzene. This charge was heated at 89 C. for 1% hours, during which water formed by the chemical reaction was removed employing a Dean-Stark trap. Ninety-one percent of the cumene hydroperoxide was consumed by the reaction. The charge was then cooled and filtered. The benzene was removed in vacuo of at about mm. Hg for 60 minutes at 25 C. About grams of hexane was added to the product mixture and the mixture was filtered through No. 3 paper to remove precipitate benzamide. The hexane was removed in vacuo of at 100 mm. Hg for 60 minutes at ambient temperature. Unreacted cumene hydroperoxide and by-product cumyl alcohol were removed by distillation using a water bath at a maximum temperature of 93 C. The residue was centrifuged for 1 hour at 10,000 r.p.m. in a Servall SS3 centrifuge having an 88-34 rotor. The product, 4-[2-(trimethoxysilyl) ethyl]curnyl cumyl peroxide, was obtained as 26.1 grams 39.3% purity as determined by active oxygen analysis by HI cleavage.

EXAMPLE 2 A reaction was prepared by mixing 7.6 grams of cumene hydroperoxide (83% purity), 23.10 grams of 4-[2-(triethoxysilyl)ethyl]cyclohexene (prepared by reacting 4- vinylcyclohexene and trimethoxysilane with chloroplatinic acid catalyst), 0.100 gram of copper (I) chloride, 0.500 gram of benzamide and 44 grams of benzene. The charge was refluxed 89 C. for 5 hours, during which water formed by the chemical reaction was removed via a Dean-Stark trap. Most of the cumene hydroperoxide (viz. 90.6%) was consumed by the reaction. The charge was then cooled and filtered through a No. 3 paper. Benzene was removed in vacuo of 100 mm. Hg for 60 minutes at ambient temperature. By-product and unreacted starting material were both removed by vacuum distillation at 0.04 mm. Hg, using a water bath as heat source to a maximum temperature of 89 C. The distilled residue was centrifuged for 30 minutes at 10,000 r.p.m. in a Servall SS3 centrifuge using an 55-34 rotor. The product, was 8.1 grams 5-[2-(trimethoxysilyl)ethyl]-3-cyclohexenyl cumyl peroxide and the isomer 4-[2-(trimethoxysilyl)ethyl]-3-cyclohexenyl cumyl peroxide. Active oxygen analysis by HI cleavage indicated 54.8% purity.

5 EXAMPLE 3 A test tube was sparged with argon and charged with 10.5 parts of methyl methacrylate (distilled, boiling point of 53 C. at 133 mm. Hg) and 0.1 part of 4-[2-(trimethoxysilyl)ethyl]cumyl cumyl peroxide. The tube was heated in an oil bath starting at 100 C. and approaching 250 C. The charge became viscous within 15 minutes (200 C.) and solid after 45 minutes (250 C.).

What is claimed is:

1. A silyl alkyl alkyl peroxide having the general formula;

wherein X is a hydrolyzable functional radical, R is hydrogen or a monovalent organic group which is bonded to the silicon atom through a carbon to silicon bond, R is a divalent hydrocarbon radical containing from 1 to about 18 carbon atoms and which is a member selected from the group consisting of alkenylene, cycloalkenylene, alkarylal-kylene and aralkylene, R" is a mem- 2O her which contains about 1 to 18 carbon atoms and is selected from the group consisting of alkyl cycloalkyl and aralkyl, and wherein n is an integer from 0 to 2 inclusive.

2. The hydrolyzates of the compound of claim 1. 3. The compound of claim 1, wherein X is a halide. 4. The compound of claim 1, wherein X is an alkoxy.

References Cited UNITED STATES PATENTS 2,970,982 2/1961 Bluestein 260448.2 B X 2,997,479 8/1961 Jenkner 260-44.8 R 3,076,852 2/ 1963 Lohringer et al.

DANIEL E. WYMAN, Primary Examiner P. F. SHAVER, Assistant Examiner U.S. Cl. X.R. 260-46.5, 448.8 R

t UNITED STATES PATENT OFFICE CERTIFICATEv OF CORRECTION Patent No. 3.772.349 Dated Novegber 13. 1973 Inventor(s) John Richard Joy It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 46, "rubber" should read --rubbers--; line 64, that portion of the formula, "SIROOR" should read --SiR'00R"--'.

should, read --phenyldimethylmonochlorosilane--; lines 66 67; delete "'of this invention can peroxy silanes"-and insert that i the alkyl alkyl peroxysilanes I Column 6, n before "18" insert ;--ab.out-. v

Signed and sealed this 17th day of December 1974.

(st-AL) Attest:

McCOY M. GIBSON JR, C. MARSHALL DANN .Attesting Officer Commissioner of Patents' Column 3', line 25, "phenylmethylmonochlorosilane" FORM P0-105O (10-69) uscoMM-Dc scan-Pea k U.5. GOVERQUAENT PRINTING OFFICE I969 0-366-336. 

